As this kind of polarized electromagnet, an operating electromagnet is linked to a contact mechanism of an electromagnetic contactor, or the like, and contact portions are driven to open and close by the suctioning action of the electromagnet. With regard to the operating electromagnet, one is known wherein a polarized electromagnet is employed in order to cause the electromagnet to be stably held in a pole open position in a non-excited condition (for example, refer to Patent Document 1).
As there is a demand for downsizing this kind of polarized magnet, it has heretofore had a spool 102 indicated by the dash-dotted line in FIG. 15, around which is wound an exciting coil 100, and through which is inserted a plunger 101, as shown in FIGS. 15 to 18. There has been a proposal of a polarized electromagnet that has a configuration wherein an interior yoke 104 is inserted and fixed in a flange portion 103 of the spool 102, an exterior yoke 105 is disposed for a predetermined distance to the outer side of the interior yoke 104, and a permanent magnet 106 is disposed between the interior yoke 104 and exterior yoke 105. Herein, the interior yoke 104 is formed in an approximate L-shape of a flat plate portion 104a along the central axis of the spool 102, an inclined plate portion 104b that extends at an inclination diagonally inward from the leading end of the flat plate portion 104a, and an extending plate portion 104c that extends inward from the leading end of the inclined plate portion 104b in a direction perpendicular to the central axis of the spool 102. Also, the exterior yoke 105 has a flat plate portion 105a, an inclined plate portion 105b, and an extending portion 105c, respectively opposing the flat plate portion 104a, inclined plate portion 104b, and extending plate portion 104c of the interior yoke 104, maintaining a predetermined distance on the outer side. Also, the exterior yoke 105 has a bent portion 105d bent inward from the other end side of the flat plate portion 105a, and is formed in a C shape seen from above of the flat plate portion 105a, inclined plate portion 105b, extending portion 105c, and bent portion 105d. Furthermore, armatures 107 and 108 are fixed and held at the left and right ends of the plunger 101. Herein, the armature 107 is disposed between the interior yoke 104 and exterior yoke 105, and the armature 108 is disposed on the outer side of the exterior yoke 105.
An operation of the polarized electromagnet having the heretofore described configuration is such that, in a condition in which the exciting coil 100 is in a non-excited condition, the plunger 101 is biased to the pole open position by an unshown return spring, and the armature 107 is held in a condition in which it is suctioned to the extending plate portion 104c of the interior yoke 104, as shown in FIG. 15.
From this condition, if the exciting coil 100 is energized and excited to a polarity reverse to that of the permanent magnet 106, a suction force acts between the left and right armatures 107 and 108 of the plunger 101 and the exterior yoke 105. At the same time, a repulsion force acts between the left side armature 107 and the interior yoke 104. Because of this, the plunger 101 moves to the left against the spring force of the return spring, and the armatures 107 and 108 are adsorbed to the exterior yoke 105.
Related Art Documents
Patent Documents
Patent Document 1: JP-A-1-315920